How to completely erase all data on a disk?

[bandXtrb]

I would like to thoroughly remove all my data from my hard disk. If I format with FORMAT.COM using the "Unconditional Format" switch, will that acccomplish this goal?

Description:

<< /U - This FORMAT.COM parameter performs an UNCONDITIONAL format, which DESTROYS every byte of data on ANY hard disk/floppy by overwriting it with hex F6h. >>

By the way, I don't want to physically destroy the disk, I want to sell it.

Thanks, and alternative suggestions welcome.

 

[RedShirt]

Yeah, That will get rid of everything...

Basically that hex number is going to be written repeadedly on the drive until the format is done, which overwrites the information that was there.

 

[Challenger]

I kind of doubt if it will destroy the disk

<< This FORMAT.COM parameter performs an UNCONDITIONAL format, which DESTROYS every byte of data on ANY hard disk/floppy by overwriting it with hex F6h.

<<


Looks like it destoys only data
😉

 

[arcas]

Coming from primarily a Unix environment, I'm not familiar with format.com but if you have access to a linux or freebsd box, you could attach the drive (don't mount it!) and do something along the lines of "dd if=/dev/zero of=/dev/hdg bs=1M count=XYZ" assuming the OS recognizes the drive as hdg and where XYZ is the number of MB of the whole drive. If you're really paranoid, you could replace "/dev/zero with /dev/urandom" and run it in a loop overnight so that each sector is overwritten dozens of times. If you do the /dev/urandom thing, you'll probably want to do one final pass with /dev/zero just to tidy everything up.

I've done this several times from x86 linux boxes with good results but note that the one time I tried it from a Solaris box, Solaris refused to recognize the drive afterwards. Stupid Solaris.

 

[bandXtrb]

<< Looks like it destoys only data >>

Oops, heh. That's what I meant. I was just trying to ward off jokes like "Smash it with a hammer" or "toss it out the window." 🙂

 

[jlemieux]

I use 10 or 25 passes with autoclave. I would suggest you try that if the data is sensitive.

You can find info here.
http://staff.washington.edu/jdlarios/autoclave/